In[1]:=

<<Graphics`Graphics`

Laplace transform of an SD pulse with no tail

In[2]:=

a = (UnitStep[t] - UnitStep[t - 1])

Out[2]=

-UnitStep[-1 + t] + UnitStep[t]

In[3]:=

Plot[a, {t, -1, 3}, ImageSize→600]

[Graphics:HTMLFiles/index_5.gif]

Out[3]=

-Graphics -

In[4]:=

LaplaceTransform[a, t, s]

Out[4]=

1/s - ^(-s)/s

change s to jw

In[5]:=

b = 1/( w) - ^(- w)/( w)

Out[5]=

-/w + ( ^(- w))/w

In[6]:=

Plot[Abs[b], {w, -20, 20}, ImageSize→600]

[Graphics:HTMLFiles/index_12.gif]

Out[6]=

-Graphics -

In[7]:=

c = ^(-6) (UnitStep[t] - UnitStep[t - 600 * 10^(-9)]) ^(10^7t)

Out[7]=

^(-6 + 10000000 t) (-UnitStep[-3/5000000 + t] + UnitStep[t])

In[8]:=

LaplaceTransform[c, t, s]

Out[8]=

1/(^6 (-10000000 + s)) - ^(-3 s/5000000)/(-10000000 + s)

Replace s with jw

In[9]:=

d = 1/(^6 (-10000000 +  w)) - ^(-3  w/5000000)/(-10000000 +  w)

Out[9]=

1/(^6 (-10000000 +  w)) - ^(-(3  w)/5000000)/(-10000000 +  w)

In[10]:=

1/(^6 (-10000000 +  w)) - ^(-(3  w)/5000000)/(-10000000 +  w)

Out[10]=

1/(^6 (-10000000 +  w)) - ^(-(3  w)/5000000)/(-10000000 +  w)

In[11]:=

Plot[Abs[d], {w, -1 * 10^8, 1 * 10^8}, ImageSize→600]

[Graphics:HTMLFiles/index_23.gif]

Out[11]=

-Graphics -

In[12]:=

LogLinearPlot[20 * Log[Abs[d]]/Log[10], {w, 10^5, 1 * 10^9}, ImageSize→600]

[Graphics:HTMLFiles/index_26.gif]

Out[12]=

-Graphics -

In[13]:=

Plot[180/π * ArcTan[Im[d]/Re[d]], {w, 1, 1 * 10^7}, ImageSize→600]

[Graphics:HTMLFiles/index_29.gif]

Out[13]=

-Graphics -


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